Multi-unit rotary mechanism

ABSTRACT

A modular two-unit rotary piston mechanism, each unit having a rotor, and a common mainshaft having a pair of eccentrics which are rotatively offset by 120 degrees and which support the rotors; this module is especially useful in forming a triple engine by coupling a single unit rotor to the common mainshaft so that the eccentric of the single unit is rotatively offset 120 so degrees from both eccentrics of the two-unit module.

The invention herein described was made in the course of, or underContract No. N000 24-77-C-5324 with the Department of the Navy and theGovernment is licensed under the patent and has minimum rights set forthin ASPR Section 7-302.23(a).

BACKGROUND OF THE INVENTION

This invention relates to multi-unit rotary mechanisms of the typedisclosed in U.S. Pat. No. 2,988,065, granted June 13, 1961, to Wankelet al, and particularly to such an engine designed for operation as astratified charge engine, for example, as disclosed in U.S. Pat. No.3,246,636, granted Apr. 19, 1966 to Bentele and U.S. Pat. No. 3,894,518,granted July 15, 1975 to Gavrun et al.

In multi-unit, rotary piston mechanisms comprising more than two units(a unit being one rotor supported on a mainshaft for planetary rotationin a housing cavity and the housing cavity defining the cavity) such asexemplified in U.S. Pat. No. 3,077,867, granted Feb. 19, 1963, to Froedeet al, are utilized when it is desired to provide increased power outputby combining a plurality of rotary units into a single power plant.Preferably, such multiple rotary engine power plants should have auniform interval between the firing of the working chambers, axiallyaligned positions for both the inlet and outlet passages of the rotaryengine units as well as maximizing the commonality of parts.

One form of triple rotor engine can be made by combining a conventional"stand-alone" two-unit rotary engine; that is, an engine which isindependently functionally operative without the necessity ofmodifications such as changes in engine balance or ignition interval,with a single unit engine. Such a conventional stand-alone two-unitengine would have its rotor eccentrics offset by 180 degrees in order toprovide uniform intervals between the firing of the working chambers asis exemplified in the two-unit rotary engines of the aforementionedFroede et al patent. Coupling such a two-unit rotary engine to anothersingle unit rotary engine will inherently result in a triple rotorengine having unequal firing intervals with the inherent disadvantages.Ideally, a triple rotary engine should have equal interval of firingignition as exemplified in the U.S. Pat. No. 3,528,084, granted Sept. 8,1970, to Hohenlohe wherein an integral three rotor engine is shownhaving its eccentrics rotatively offset by 120 degrees.

Accordingly, it is an object of this invention to provide a modulartwo-unit, rotary piston engine, which, without modification, can beeasily coupled to a single unit rotary piston engine to create a tripleengine having equal firing intervals and the smoothest possible output.

It is a further object of this invention to provide a modular two-unit,rotary piston engine which is separately, rotatively, dynamicallybalanced, which can be easily coupled to a single unit rotary pistonengine which is similarly balanced to create a triple rotor enginehaving equal firing intervals and the smoothest possible output.

A still further object of this invention is to provide a triple rotorrotary engine having completely aligned rotor housings consisting of amodular, stand-alone two-unit, rotary piston engine coupled to a singleunit piston engine which triple rotor engine achieves the smoothestpossible output.

The foregoing and related objects are obtained in accordance with theinvention which in its broader aspects provides a modular two-unit,rotary piston mechanism, each unit having a housing forming a cavity inwhich a rotor is eccentrically supported for planetary rotation so as toform a plurality of working chambers defined between the rotor and itshousing which successively expand and contract in volumetric size as therotor planetates relative to the housing. The housing is provided withan intake port means for introducing air into the working chambers andan exhaust port means for discharging products of combustion from theworking chambers, a common mainshaft extending coaxially through thehousing's cavities and having a pair of axially-shaped eccentricportions, one for each housing cavity. This pair of eccentric portionsare rotatively offset 120 degrees.

In a narrower aspect of this invention, the intake port means of eachhousing are disposed one behind the other when viewed in a directionparallel to the shaft axis and where the exhaust port means of eachhousing are similarly disposed.

In another narrower aspect of this invention, a triple rotor engine isformed comprising the aforesaid two-unit engine and a single unitengine. The two-unit engine is coupled to the single unit engine in sucha manner that the eccentric portion of the single unit engine isrotatively offset 120 degrees from the eccentrics of the two-unitengine.

Other objects of the invention will become apparent upon reading thespecification taken in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic traverse view of a triple rotor engine accordingto the invention, each unit being shown in traverse section which, forclarity of the drawing, is shown side by side, although in the actualengine, each unit would be directly behind the other; and

FIG. 2 is a schematic axial sectional view of the engine of FIG. 1, eachunit being shown without its rotor.

DESCRIPTION OF A PREFERRED EMBODIMENT

Now, referring to the drawings, a triple engine is schematicallyindicated at 10, comprising a two-unit engine 12 coupled to a singleunit engine 14. The two-unit engine 12 comprises a first and secondrotary piston mechanism, I and II, or 16 and 18, and the single unitengine 14 comprises a third rotary piston mechanism III or 20, coupledtogether by coupling means 22, each rotary piston mechanism beinggenerally similar to that described in the aforementioned patents andsimilar to each other. FIG. 1 shows each unit in traverse section; forclarity of illustration, however, the engine units or rotary pistonmechanisms are shown side by side although in the actual engine, eachunit would be directly behind the other as illustrated in FIG. 2, whichfigure is a schematic axial section view of the engine of FIG. 1.

Each rotary piston mechanism is schematically shown as comprising anouter body or housing 24 including two axially-spaced end housing 26 and28 and an intermediate or rotor housing 30, these housing parts beingsecured together to form an engine internal cavity 32. An inner body orrotor 34 (shown only in FIG. 1), is journaled for rotation within thehousing cavity 32 on an eccentric portion 36, 38 and 40 of a firstsecond and third rotary piston mechanism I, II and III, respectively,and eccentric portions 36 and 38 are supported for rotation on a commonmainshaft 42 and eccentric portion 40 is supported for rotation on itsown mainshaft 44. Common mainshaft 42 extends coaxially through itshousing cavities 32 and is supported at its ends by end housings 26 and28. Similarly, mainshaft 44 extends coaxially through its single housingcavity 32 and is supported at its ends by end housings 26 and 28.

Each intermediate housing 30 has a peripheral inner surface or trochoidsurface 46 which is illustrated as having a two-lobe profile whichpreferably is basically epitrochoidal in configuration said two lobesjoining at junctions 48 and 50 which are disposed relatively near to thepiston mechanism's axis. The rotor 34 has a generally triangular profilewith its apex portions having sealing cooperation with the epitrochoidalsurface or peripheral inner surface 46 to form three working chambers 52between the rotor 34 and housing walls 26 and 28.

Each piston mechanism includes suitable timing gears (not shown) betweenthe rotor 34 and its housing 24 to maintain the requisite angularrelationship of the rotor, housing and shaft; such timing gears areconventional and may be similar to those illustrated in the U.S. patentsto Bentele et al., U.S. Pat. No. 3,111,261, granted Nov. 19, 1963, andJones et al., U.S. Pat. No. 3,655,302, granted Apr. 11, 1972. Inaddition, each engine unit's housing includes an air intake passage orport 54 disposed adjacent to and on one side of one lobe 48 of thetrochoid surface 46 and an exhaust passage or port 56 disposed on theother side of said lobe 48; the exhaust ports 56 are connected to acommon exhaust conduit 58. Combustion is initiated in the engine workingchambers adjacent to the other lobe 50 of the trochoid surface by,preferably a stratified charge injection system comprising thecombination of a fuel injection nozzle (not shown) and adjacent ignitionmeans 60, such as a spark plug, as is disclosed in the U.S. patents toBentele, U.S. Pat. No. 3,246,636 and Jones, U.S. Pat. No. 3,698,364.

Each piston mechanism, as thus far described, functions with rotor 34rotating in the direction of the arrow in FIG. 1, so that each workingchamber 52 periodically increases from a minimum volume condition, whenit is located adjacent to lobe junction 48 and opens the intake port 54,to a maximum volume condition and closes the intake port 54 and thensaid chamber decreases in volume to compress the air trapped thereinuntil the working chamber 52 again reaches a maximum volume condition atlobe junction 50. Thereafter, the volume of said chamber increases to amaximum under expanding gas pressure and then decreases to a minimum asthe chamber comes into communication with the exhaust port 56 at lobejunction 48 to thus complete the cycle. To effect combustion of fuel ineach working chamber 32 after substantial compression of air therein,the stratified charge injection system, including spark plug 60, isprovided.

As can be seen in FIG. 2, the profiles of the cavities 32 of all threehousings 24 are axially aligned. In addition, the inlet ports 54 arelikewise aligned; that is, when viewed in a direction parallel to thecrankshaft's axis the single inlet port 54 of each housing 24 isdirectly behind the other. The outlet ports 56 are similarly alsoaxially aligned. The crankshaft eccentric portions 36 and 38 of commonmainshaft 42 of piston mechanisms I and II are, however, rotativelyoffset by 120 degrees. The crankshaft eccentric portion 40 of thecrankshaft 44 of piston mechanism III of single unit engine 14, iscoupled to the two-unit engine 12 through coupling means 22 (describedin more detail infra) so that eccentric portion 40 of the single unitengine 14, is rotatively offset 120 degrees from the eccentrics 36 and38 of the two-unit engine 12 thereby forming a triple rotor enginehaving its three eccentrics equally, rotatively angularly offset, 120degrees apart.

It can be seen from the views of FIG. 1 that the firing positions of theworking chambers of each of the three piston mechanisms are equallyspaced or staggered 120 degrees as regards their cycle, from those ofthe adjacent piston mechanism thereby ensuring even firing sequences andsmoothest possible output.

As shown in FIGS. 1 and 2, the eccentric portions 36 and 38 of commonmainshaft 42 of piston mechanism I and II are rotatively displaced 120degrees relative to each other and this common mainshaft 42 is providedwith conventional counterweight means 62 for providing separaterotative, dynamic balance of this mainshaft 42 in order to balance thecentrifugal forces on the rotating eccentric parts. Similarly, separaterotative dynamic balancing is conventionally provided mainshaft 44 ofpiston mechanism III by providing conventional counterweight means 62.The techniques for engine balance are described, for example, in chapter7 of Mechanics of Machinery by Ham & Crane, 1948, published byMcGraw-Hill Book Co.

The coupling means 22, utilized to connect the mainshafts of thetwo-unit engine 12 to the single unit engine 14 so as to permit angular,radial and endwise axial flexibility relative to the mainshaft axes ofthese engines and torsional stiffness for torque transmission betweenthese connected mainshafts while eliminating the transmission of dynamicbending moments, is described in detail, for example, in co-pendingpatent application of Jones and Corwin, Multi-Unit Rotary PistonMechanism and Mainshaft Coupling Therefor, filed Apr. 4, 1979, of thesame assignee, the relevant portions of which are incorporated herein byreference. Furthermore, though the schematic drawing of FIG. 2 showseach of unit I and II of the two-unit engine 12 as having housings whichare separated from each other, in actual construction these two unitsare subassemblies of a single two rotor (rotary piston) unit, asdescribed, for example in the aforementioned co-pending patentapplication.

It is believed now readily apparent that the present invention providesa "stand alone", modular two-unit rotary piston engine, which, whenconnected as described, to a single conventional one unit rotary pistonengine which is conventionally completely and separately balanced, atriple rotor engine is capable of being formed which engine has itsrotor housing aligned as per conventional engine assembly methods whilehaving regular, even, firing sequences thereby providing the smoothestpossible output, and while having a very high degree of commonality ofparts. With regard to the latter advantage, all that is required toconvert a conventional two-unit rotary piston engine is to replace itscommon mainshaft by one having eccentric portions offset by 120 degreesinstead of 180 degrees and replace its counterweights by new ones. Allother parts will be common, both for the new modular two-unit rotarypiston mechanism of the present invention and the add-on, or coupled,single unit engine which when connected results in a triple rotorengine.

What is claimed is:
 1. A three-rotor modular rotary piston mechanismconsisting of a single rotor mechanism unit and a two-rotor mechanismunit with each mechanism unit having a mainshaft and wherein each unithas a housing forming a cavity for each rotor which is supported forplanetary rotation in the cavity on an eccentric portion of itsassociated mainshaft so as to form a plurality of working chambersdefined between the rotor and housing and which working chambers expandand contract in volumetric size as the rotor planetates relative to thehousing, the three-rotor modular mechanism comprising:(a) the mainshaftfor the two-rotor mechanism unit having its associated eccentricportions angularly offset from each other by 120 degrees; (b)counterweights for each of the single rotor and two-rotor mechanismunits being arranged relative to the associated mainshaft to dynamicallybalance each rotor mechanism unit; (c) coupling means for connecting themainshaft of each rotor mechanism unit so as to permit angular, radialand endwise flexibility and torsional stiffness for torque transmissionbetween the connected mainshafts; and (d) said coupling meansinterconnecting the mainshafts so that the eccentric portion of thesingle unit is angularly offset 120 degress from the next adjacenteccentric portion of the mainshaft of the two-rotor mechanism unit tothus provide all eccentric portions of the three-rotor mechanismangularly displaced from each other 120 degrees.
 2. The mechanism ofclaim 1 wherein intake port means is provided for introducing fluid intothe working chambers and exhaust port means is provided to conduct fluidfrom the working chambers and wherein a first manifold is connected topass fluid into each of the intake port means of each of said rotarymechanism units and a second manifold is connected to receive fluid fromsaid exhaust port means of each of said rotary mechanism units.
 3. Themechanism of claim 2 wherein said single rotor unit and two-rotormechanism units are coaxially disposed with the profiles of all theirhousing cavities being axially aligned.